Refactor single-file module to a directory module

[Deconstrained]

We need to refactor this project from a single-file module into a multi-file module. Long-term, it's what we will need in order to make the codebase more maintainable, because we will need to add child classes to support the extreme antipatterns of the new integration APIs (i.e. using a different hostname for some endpoints but not all).

This also would un-block #26.